Laminating resins having low organic emissions (II)

ABSTRACT

A laminating resin is made from (1) an unsaturated polyester resin comprising maleic acid, phthalic acid, and glycol(s), (2) a diacrylate or dimethacrylate of alkoxylated bisphenol-A, and (3) ethylene glycol dimethacrylate. The resin requires no styrene to achieve excellent laminating resin properties, and is significantly inhibited from emitting volatiles during use.

RELATED APPLICATIONS

This application is a continuation-in-part of our application Ser. No. 024,022, filed Mar. 1, 1993, now abandoned, of the same title.

TECHNICAL FIELD

This invention relates to resin compositions which cure as they are shaped, laminated, brushed, sprayed or otherwise more or less incrementally placed into the space where they are to form a product; such resins are broadly known as laminating resins, commonly have an unsaturated polyester resin base, are mixed with glass fiber reinforcement, and nearly always are employed in a solution of an organic monomer such as styrene. The organic monomer is intended to copolymerize with the resin but typically and notoriously may also tend to volatilize in significant amounts into the workplace environment. The present invention is a composition and method which can be used in existing equipment, procedures, and workplaces, but which will emit far less monomer than the typical laminating resin and method heretofore.

BACKGROUND OF THE INVENTION

Many attempts have been made to devise laminating resins having low volatile emissions and still meet the physical specifications and other desirable properties of the end products, while remaining relatively easy to use. In Lee U.S. Pat. No. 4,465,806, for example, a more or less conventional unsaturated polyester resin is combined with, instead of the usual styrene, a reaction product of a polyepoxy compound and acrylic or methacrylic acid which may be the diacrylate of a polyglycidyl ether of bisphenol-A. These compounds are made from epoxy compounds, and the author of U.S. Pat. No. 4,465,806 requires that a significant portion of the epoxy groups be unreacted for use in their resin. Moreover, unlike the present invention, they form pendant OH groups.

Ethoxylated, difunctional, bisphenol-A has been used in the past as an ingredient in various types of resins, generally resins which include a significant diisocyanate component, as in Ford, Jr. et al U.S. Pat. No. 3,876,726.

European Patent Application 0 234 692 discloses a composition said to be useful as a molding resin, having the virtue of a low residual monomer concentration in the final product. The gist of the disclosure appears to be that dimethacrylates such as ethoxylated bisphenol-A dimethacrylate can be used as components of otherwise more or less conventional unsaturated polyester resins to reduce the amount of residual styrene monomer in contained molding processes such as cell molding, compression molding, and sheet molding. See also Reid and Rex U.S. Pat. No. 5,202,366, which includes a low-profile additive in a similar composition.

The daunting problem of volatile emissions during spray-up or other laminating procedures has until now been unsolved. Applicants' dramatic results detailed herein show that lamination can be used with significantly reduced emissions in the workplace.

SUMMARY OF THE INVENTION

Our new laminating resin comprises three components- The first is a base resin comprising glycols and unsaturated dicarboxylic acids; optionally the base resin may also contain a saturated dicarboxylic acid. In polymeric form, they are typically maleic and phthalic acid residues, with optional isophthalic residues, interspersed with glycol residues. These glycols are commonly ethylene glycol, diethylene glycol, propylene glycol and dipropylene glycol, usually as mixtures, but many other glycols can be utilized; dicyclopentadiene may be included as well, as is known in the art. The second component is a diacrylate or dimethacrylate of alkoxylated bisphenol-A of the formula ##STR1## where m and n are independently numbers from 1 to about 10, and R¹ and R² are independently, in each alkoxy group, hydrogen or CH₃. Hydroxyethyl or hydroxypropyl groups should comprise about 19-71% of the weight of this ingredient. These two ingredients may be present in weight ratios of about 2.0:1 to about 0.5:1. The composition also includes about 20-60% based on the total of the two above ingredients of ethylene glycol dimethacrylate. The above-described composition may also include from 1% to about 10% of N-vinyl pyrrolidone or 1% to about 20% cyclohexyl methacrylate or both, and/or 1% to about 30% vinyl toluene or divinyl benzene or a mixture thereof. Since our objective is to design a composition which works very well as a laminating resin without significant styrene emissions, the addition of styrene to the recipe defeats that purpose and is not recommended, but the composition will continue to be operable as an excellent laminating resin even though some styrene is included. The composition will also tolerate many other minor ingredients known to be useful in the unsaturated polyester and laminating art. A volatility of 20.0 g/m² or less, as measured by the test of Section 1162 of the Regulations of the South Coast (California) Air Quality District, was significantly achieved by applicants in the present invention. In fact, applicants' resins all measured under 10.0 g/m².

DETAILED DESCRIPTION OF THE INVENTION

While the problem at hand is to create a formulation which drastically differs from commercial standard laminating resins in terms of volatile emissions during application, the market dictates that it must be accomplished without significantly altering the widely used equipment and techniques of application. Accordingly, the following criteria are to be kept in mind at all times:

1. Reduced emission of volatile organic compounds--regulations will become more stringent with time.

2. Less potential hazard to human health and the environment--regulations will also become more stringent with time.

3. Minimal increase in cost when commercialized, and reason to believe cost will be reduced in the long run.

4. Compatibility between components of the resin system.

5. Reactivity that is similar to that of styrenated polyester resins.

6. Viscosity that is similar to that of styrenated polyester resins--100 to 400 cps.

7. Physical properties similar to or better than those of styrenated polyester resin.

8. Ability to wet glass and bond to other components of an assembly.

Persons skilled in the art will realize that number 7, relating to physical properties of the final product, can by itself include several important specifications. Thus, the problem is not simply one of finding a monomer which is not as volatile or objectionable as styrene. Rather, many criteria have to be balanced, and, with thousands of chemicals to consider, analysis of the combinations and their effects is extremely difficult. One must decide on the important functions and properties, settle on a systematic but simple screening process, and try to develop a short list of prospective formulations which have a good chance of meeting all the criteria within a practical time period.

The proliferation of input variables to attain these objectives may be further appreciated by considering the more or less conventional unsaturated polyester compositions which may be used as a base. They are prepared by polycondensation of polycarboxylic acid derivatives, one of which must be an alpha, beta-ethylenically unsaturated polycarboxylic acid, and polyols. By polycarboxylic acid derivatives we mean to include polycarboxylic acids, their esters of lower alcohols, their acid chlorides and their anhydrides.

The ratio of polycarboxylic acid to polyol is usually a 1:1 molar ratio. However, in most esterification processes, a slight excess of polyol is utilized to compensate for polyol losses during esterification. Also, although dicarboxylic acids and diols are most frequently utilized and the 1:1 molar ratio is prevalent, the utilization of triols and the like requires the ratio of acid to polyol to be stated more precisely as one equivalent of acid per equivalent of polyol.

The unsaturated polyesters useful in this invention may be prepared from an acid mixture wherein the unsaturated polycarboxylic acid comprises as little as 20 mole percent of the total acids present, although it is generally preferred that the unsaturated polycarboxylic acid comprises about 30% or more of the total acid content.

Some of the unsaturated polycarboxylic acids useful in preparing unsaturated polyesters used in this invention include:

    ______________________________________                                         Maleic acid        Citraconic acid                                             Fumaric acid       Glutaconic acid                                             Itaconic acid      Chloromaleic acid                                           Mesaconic acid                                                                 ______________________________________                                    

and the like, wherein the term "acid" is used to include the corresponding anhydrides where such anhydrides exist.

Some of the saturated and aromatically unsaturated polycarboxylic acids optionally useful in preparing unsaturated polyesters used in this invention include:

    ______________________________________                                         Phthalic acid      Isophthalic acid                                            Tetrahydrophthalic acid                                                                           Hexahydrophthalic acid                                      Endomethylene tetra-                                                           hydrophthalic acid                                                             Tetrachlorophthalic acid                                                                          Glutaric acid                                               Hexachloroendomethylene                                                        tetrahydrophthalic acid                                                        Succinic acid      Suberic acid                                                Adipic acid        Sebacic acid                                                ______________________________________                                    

and the like, wherein the term "acid" includes the corresponding anhydrides where such anhydrides exist.

Polyols useful in preparing polyesters for use in this invention are polyfunctional alcohols of the type conventionally utilized in polyester preparation. Such polyols include:

    ______________________________________                                         Ethylene glycol     1,5 propanediol                                            Propylene glycol    Triethylene glycol                                         Butylene glycol     Glycerol                                                   Diethylene glycol   1,4,6-hexanetriol                                          Trimethylolpropane  Trimethylolethane                                          Dipropylene glycol  Pentaerythritol                                            Neopentyl glycol                                                               Alkoxylated 2,2-bis-                                                           (4-hydroxyphenyl) propane                                                      ______________________________________                                    

and the like. Although diols are generally preferred in the preparation of unsaturated polyesters, the more functional polyols, i.e. polyols having a functionality of three to five, are sometimes used.

In addition, dicyclopentadiene may be included and may be considered a normal part of the "base resin" as used herein.

During the development of the formulation, various monomers and monomer substitutes were screened, using two different "base" resins--one having dicyclopentadiene as a major ingredient and one without dicyclopentadiene. Following are results for the base resin without dicyclopentadiene:

A base resin composition (hereafter designated "Resin A") was prepared having the following ingredients:

    ______________________________________                                         Base Resin*      60 parts                                                                       by weight                                                     12% Cobalt (Promoter)                                                                           00.30                                                         Potassium (Co-promoter)                                                                         00.20                                                         N,N-Dimethylacetoacetamide                                                                      00.30                                                         (Accelerator)                                                                  DDM-9 (Initiator)                                                                               01.50                                                         Monomer (as indicated below)                                                                    40                                                            ______________________________________                                                          Parts by  lbs/100                                             *Base Resin (Polymer)                                                                           weight    lbs     lbs/60 lbs                                  ______________________________________                                         Propylene Glycol 22.788     31.97  19.18                                       Diethylene Glycol                                                                               04.937     6.93    4.16                                       Phthalic Anhydride                                                                              32.734     45.92  27.55                                       Maleic Anhydride 10.820     15.18   9.11                                                        71.279    100.00  60.00                                       ______________________________________                                    

The following "monomers" were utilized with Resin A:

    ______________________________________                                                                      Exo-  Gel   Inter-                                                     Visc-   therm Time  val                                   Monomer     Mod L.sup.1)                                                                            osity   °F.                                                                           min:sec                                                                              min:sec                               ______________________________________                                         Styrene     0.120    low     335   4:30  4:39                                  Vinyl Toluene                                                                              0.120    low     317   4:50  5:04                                  Diallyl phthalate                                                                          0.000    high    119   19:27 27:43                                 Methacrylates                                                                  n-butyl     0.001    low     186   40:58 5:28                                  n-hexyl     0.001    incom-                                                                         patible                                                   isodecyl    0.001    incom-                                                                         patible                                                   cyclohexyl  0.001    high*   287   16:50 3:50                                  2-phenoxyethyl                                                                             0.001    high    196   8:45  3:29                                  allyl       0.001    low     331   18:20 3:37                                  2-hydroxyethyl                                                                             0.001    low     247   4:48  3:35                                  2-hydroxyethyl                                                                             0.010    low     249   4:30  3:20                                  dicyclopentyl                                                                              0.001    very    199   3:40  4:11                                                       high                                                      isobornyl   0.000    incom-                                                                         patible                                                   isophoronyl 0.010    incom-                                                                         patible                                                   Dimethacrylates                                                                1,6-hexanediol                                                                             0.001    high    241   7:54                                        ethylene glycol                                                                            0.001    low     275   2:48  3:37                                  (EG)                                                                           ethylene glycol                                                                            0.005    low     274   2:52  3:50                                  diethylene glycol                                                                          0.001    med-    >210  4:03  2:12                                                       ium                                                       diethylene glycol                                                                          0.010    med-    252   5:40  3:13                                                       ium                                                       triethylene glycol                                                                         0.001    med-    241   3:18  3:17                                                       ium                                                       tetraethylene glycol                                                                       0.001    med-    229   2:52  3:46                                                       ium                                                       neopentyl glycol                                                                           0.001    high    235   4:20  4:09                                  ethoxylated BPA                                                                            0.001    very    171   8:50  7:30                                                       high                                                      C14 diol    0.001    incom-                                                                         patible                                                   Trimethacrylate                                                                trimethylol propane                                                                        0.001    high    228   2:28                                        Mixtures                                                                       30 EG dimeth-                                                                  acrylate/                                                                      10 N-vinyl pyr-                                                                            0.010    med-    295   1:49  3:12                                  rolidinone           ium                                                       30 EG dimeth-                                                                  acrylate/                                                                      10 divinyl benzene                                                                         0.010    med-    286   3:11  3:29                                  30 vinyl toluene/    ium                                                       10 N-vinyl pyr-                                                                            0.200    low     289   16:10 4:44                                  rolidinone                                                                     ______________________________________                                          *This was considered unsatisfactory, but when ethoxylated BPA                  dimethacrylate was included to make a 3part mixture, viscosity was             lowered. Of all the above substitutions for monomer, only the Nvinyl           pyrrolidinone, divinyl benzene, ethylene glycol                                dimethacrylate, cyclohexyl methacrylate, and vinyl toluene were not ruled      out. The rest were eliminated from consideration because they were slow t      react with polyester as shown by long gel time and/or low exotherm or the      were not sufficiently compatible with polyester as shown by high viscosit      or the outright failure to dissolve.                                           .sup.1) Mod L is 25% hydroquinone in propylene glycol.                   

Liquid resin properties measured in the experiments reported below were gel time, (reported in the tables herein in minutes and seconds, as 13:17, for example), room temperature interval time, which is the time between gelation and the exothermic peak, room temperature exothermic peak which is the highest temperature reached in a 100 g mass of resin during the curing process, Brookfield viscosity, and Barcol hardness by ASTM D2583. For volatile emissions, we followed the Rule 1162 Standard Method for Static Volatile Emissions of the South Coast Air Quality Management District (California) which is incorporated herein by reference. This test is accepted as a predictor of volatile emissions in the workplace during spray-up lamination procedures. Its results are reported in two ways--grams per square meter of weight loss, and the time of emissions, in minutes and seconds. The latter measurement entails noting the point in time in which weight loss is no longer recorded, thus requiring that weight be monitored beyond the time noted.

The test requirements are as follows: An environment at 77° C. and 50% relative humidity is maintained. If a controlled environment is not available, conditions should be reported for which measurements are made. A 200 gm pre-promoted resin is weighed out into a suitable dry and clean container. The container is covered and placed in a 25° C. temperature bath. A balance is placed in a draft free enclosure. A gallon lid is cleaned with solvent and wiped dry. The diameter is measured to the nearest 0.1 cm. The gallon lid is placed on an inverted paper or plastic cup mounted on the balance pan. A bent paper clip is positioned in the center of the gallon lid. This weight (TARE WEIGHT) is recorded. The container is taken from the temperature bath and an appropriate volumetric or weight measure of catalyst is added. A timer is started at this point. The catalyst is mixed with the resin for one minute. The INITIAL WEIGHT is determined by pouring 100.0±0.5 gm of catalyzed resin into the can lid and recording the weight. Next, the paper clip is used to determine when the resin has hardened sufficiently to allow the resin or lid to be lifted. The time (gel time) is recorded at this point. The resin is then allowed to harden in the can lid and every 15 minutes it is reweighed until concurrent weights agree to within 0.05 gm. This is recorded as the FINAL WEIGHT. The entire procedure should be repeated until duplicate samples agree to the nearest 5 gm/m².

The volatile emissions per square meter are calculated as follows: ##EQU1##

The clear castings tests adopted were as follows:

1. Tensile strength--ASTM D638.

2. Tensile modulus--ASTM D638.

3. Elongation--ASTM D638.

4. Flexural strength--ASTM D790.

5. Flexural modulus--ASTM D790.

6. Heat deflection temperature ASTM D648.

7. Water absorption at 150° F.--ASTM D570 (modified).

The water absorption test was modified as follows: the temperature was set at 150° F. and long term immersion was set at one week. In the data reported in Table I, Resin A is as described above in terms of weight; it is, in molar equivalents, a polyester resin composed of 1.0 mole maleic anhydride, 2.0 moles phthalic anhydride, 0.42 mole diethylene glycol and 2.71 moles propylene glycol. Resin B is similar to Resin A with a lower viscosity by an adjustment of the cook, as is known in the art. Sartomer CD480 is ethoxylated bisphenol-A dimethacrylate where m and n in the above formula total 10. Sartomer 348 is ethoxylated bisphenol-A dimethacrylate where m and n in the above formula are both 1. Mod L is 25% hydroquinone and 75% propylene glycol.

From the data in Table I, it can be seen that formulations S and O have better than acceptable resin properties and clear casting properties, and have volatile emissions far less than the rate of the more or less classical commercial resin A2.

In Tables II and III, nine additional formulations are shown. From these it will be seen that cyclohexyl methacrylate causes undesirable properties when used as the only material in addition to the base resin and the ethoxylated BPA dimethacrylate. But there are extraordinarily low emissions from all nine of the formulations. The use of vinyl toluene to reduce the viscosity is certainly not detrimental to emissions results.

                  TABLE I                                                          ______________________________________                                         RESIN    A2      C2      S     Z     A1    O                                   ______________________________________                                         Resin A  60.00   60.00   40.00 35.00 35.00 --                                  Resin B  --      --      --    --    --    45.00                               Sartomer --      --      15.00 15.00 15.00 10.00                               CD480                                                                          Sartomer 348                                                                            --      --      20.00 20.00 20.00 15.00                               EG Dime- --      --      25.00 10.00 20.00 30.00                               thacrylate                                                                     Vinyl    --      40.00   --    10.00 --    --                                  Toluene                                                                        Cyclohexyl                                                                              --      --      --    10.00 --    --                                  Methacrylate                                                                   Divinyl  --      --      --    --    10.00 --                                  Benzene                                                                        Styrene  40.00   --      --    --    --    --                                  Mod L    0.20    0.22    0.06  0.12  0.12  0.06                                RESIN PRO-                                                                     PERTIES                                                                        Gel time,                                                                               12:59   13:17   21:18 18:29 11:30 5:20                                min:sec                                                                        Interval,                                                                               5:58    6:54    4:32  4:11  3:26  3:19                                min:sec                                                                        Exotherm 345     324     249   276   294   245                                 peak, °F.                                                               Viscosity,                                                                              315     340     1,390 426   624   396                                 cps, 75° F.                                                             1162 Emis-                                                                              31.5    20.6E   3.6   6.1   9.7   3.6                                 sions, G/M2                                                                    Barcol                                                                         hardness                                                                       45 minutes                                                                              45      42      47    44    52    34                                  One hour 45      43      50    48    53    36                                  24 hours 49      49      32    51    54    36                                  CLEAR                                                                          CASTING                                                                        PROPER-                                                                        TIES                                                                           Tensile  9,308   7,555   8,069 9,635 8,176 10,179                              strength, psi                                                                  Ten. mod-                                                                               0.549   0.534   0.466 0.565 0.575 0.567                               ulus, 10-5 psi                                                                 Elongation,                                                                             1.9     1.6     3.2   2.7   1.9   2.3                                 Flexural 16,008  15,317  10,475                                                                               16,889                                                                               15,780                                                                               16,013                              strength,psi                                                                   Flex mod-                                                                               0.586   0.573   0.322 0.444 0.482 0.498                               ulus, 10-5 psi                                                                 Heat deflect.                                                                           144     138     169   142   147   141                                 temp, °F.                                                               Water absor-                                                                   ption, % at                                                                    150° F.                                                                 One day  0.89    0.91    1.01  1.19  1.26  1.43                                7 days   1.89    1.89    2.12  1.65  1.76  2.14A                               ______________________________________                                          E  This value was estimated based on the difference in results caused by       using different and points tor the 1162 test.                                  A  The surfaces of the test specimens were alligatored. This indicates a       sore severe problem than the weight gain indicates.                      

                  TABLE II                                                         ______________________________________                                         Low VOC Laminating Resins Based on General Purpose                             Polyester Polymer                                                              Resin       E-3B    F-3      G-3   H-3   I-3                                   ______________________________________                                         Composition                                                                    Resin A     35.00   35.00    35.00 35.00 35.00                                 Sartomer 480                                                                               15.00   15.00    15.00 15.00 15.00                                 Sartomer 348                                                                               20.00   20.00    20.00 20.00 20.00                                 EG Dimethacrylate                                                                          --      15.00    --    15.00 20.00                                 Cyclohexyl Metha-                                                                          30.00   15.00    15.00 --    05.00                                 crylate                                                                        Vinyl Toluene                                                                              --      --       15.00 15.00 05.00                                 Mod L       00.00   00.00    00.17 00.17 00.06                                 12% Cobalt  00.30   00.30    00.30 00.30 00.30                                 16% Potassium                                                                              00.20   00.20    00.20 00.20 00.20                                 Dimethyl Ace-                                                                              00.30   00.30    00.30 00.30 00.30                                 toacetamide                                                                    Resin Properties                                                               Gel Time, min:sec                                                                          48:00   27:55    33:52 25:10 30:40                                 Interval, min:sec                                                                          10:49   05:01    07:07 03:51 05:23                                 Exotherm, °F.                                                                       229     239      244   291   258                                   Viscosity, cps                                                                             1,280   1,085    560   650   930                                   @ 75° F.                                                                Barcol-45 minutes                                                                          00.0    31.7     00.0  00.0  26.6                                  one hour    00.0    47.3     29.7  47.0  48.7                                  two hours   00.0    48.6     45.6  50.8  51.0                                  three hour  00.0    48.2     45.9  49.8  51.1                                  four hours  00.0    48.6     46.0  50.3  51.2                                  24 hours    38.2    48.4     47.2  50.7  51.5                                  1162 Emissions,                                                                            2.4     6.1      3.6   4.2   3.0                                   G/M2                                                                           Emissions, min:Sec                                                                         60:55   36:42    53:46 29:15 36:18                                 Properties of a                                                                Clear Casting                                                                  HDT, °F.                                                                            129     138      138   159   163                                   Tensile Strength, psi                                                                      9,290   8,980    9,580 9,140 6,050                                 Ten modulus,                                                                               0.451   0.481    0.485 0.544 0.587                                 10-5 psi                                                                       Elongation, %                                                                              3.10    2.40     2.50  2.00  1.20                                  Flexural Strength,                                                                         14,400  >16,130  18,400                                                                               19,660                                                                               17,150                                psi                                                                            Flex modulus,                                                                              0.488   0.520    0.662 0.664 0.633                                 10-5 psi                                                                       Water Absorption                                                               @ 150° F.                                                               24 hours    1.06    1.08     1.07  0.95  1.07                                  seven days  2.43    2.19     1.78  1.84  2.06                                  ______________________________________                                    

                  TABLE III                                                        ______________________________________                                         Low VOC Laminating Resins Based on General Purpose                             Polyester Polymer                                                              Resin       U-3     ZA      V-3    Z     Q-4                                   ______________________________________                                         Composition                                                                    Resin A     35.00   35.00   35.00  35.00 30.00                                 Sartomer 480                                                                               15.00   15.00   15.00  15.00 20.00                                 Sartomer 348                                                                               20.00   20.00   20.00  20.00 20.00                                 EG Dimethacrylate                                                                          15.00   10.00   --     10.00 30.00                                 Cyclohexyl Metha-                                                                          05.00   10.00   --     10.00 --                                    crylate                                                                        Vinyl Toluene                                                                              10.00   10.00   30.00  10.00 --                                    Mod L       00.13   00.06   00.20  00.12 00.10                                 12% Cobalt  00.30   00.30   00.30  00.30                                       16% Potassium                                                                              00.20   00.20   00.20  00.20                                       Dimethyl Ace-                                                                              00.30   00.30   00.30  00.30                                       toacetamide                                                                    Resin Properties                                                               Gel Time, min:sec                                                                          38:05   38:15   37:36  18:29 14:10                                 Interval, min:sec                                                                          06:07   07:37   09:49  04:11 4:38                                  Exotherm, °F.                                                                       277     277     273    276   233                                   Viscosity, cps                                                                             790     710     382    426   400                                   @ 75° F.                                                                Barcol-45 minutes                                                                          00.0    00.0    00.0   44.0  50.1                                  one hour    37.0    32.2    39.9   48.0  51.9                                  two hours   48.6    47.2    46.0   --    52.1                                  three hour  48.5    47.6    46.2   --    52.1                                  four hours  48.5    47.8    46.9   --    52.1                                  24 hours    48.5    48.7    46.9   51.0  52.1                                  1162 Emissions,                                                                            7.3     2.4     1.8    6.1   0.6                                   G/M2                                                                           Emissions, min:Sec                                                                         44:22   48:20   51:35  --    16:00                                 Properties of a                                                                Clear Casting                                                                  HDT, °F.                                                                            136     138     138    142   210                                   Tensile Strength, psi                                                                      10,120  10,370  9,500  9,635 5,660                                 Ten modulus,                                                                               0.489   0.540   0.501  0.565 0.516                                 10-5 psi                                                                       Elongation, %                                                                              2.70    2.60    2.30   2.70  1.30                                  Flexural Strength,                                                                         18,750  19,410  >19,150                                                                               16,889                                                                               14,550                                psi                                                                            Flex modulus,                                                                              --      --      --     0.444 0.508                                 10-5 psi                                                                       Water Absorption                                                               @ 150° F.                                                               24 hours    1.06    1.04    0.81   1.19                                        seven days  1.78    1.87    1.43   1.65                                        ______________________________________                                    

Based on experimental work performed subsequent to the filing of the parent application Ser. No. 024,022, ethylene glycol dimethacrylate is useful in our composition and method. Accordingly, our invention comprises a composition comprising (a) the base polyester polymer (resin) as described above and the alkoxylated bisphenol-A diacrylate or dimethacrylate in a ratio of 2:1 to 0.5:1 and (b) about 20% to about 60%, based on the total of (a) and (b), of ethylene glycol dimethacrylate. In Tables I, II, and III, the various "Sartomer" compositions, i.e. the ethoxylated bisphenol-A dimethacrylates, have 2 and 10 ethoxy groups on both sides of the bisphenol-A; however, we may employ a single compound or compounds having any variation of combinations of ethoxy or propoxy groups from two to about 20 groups, preferably a total of 2 to 8 alkoxy groups. 

We claim:
 1. Method of laminating a solid formed body comprising (a) providing a forming surface having a desired positive or negative shape, (b) providing a liquid mixture comprising (1) about two parts by weight unsaturated polyester resin, (2) about one part to about four parts by weight alkoxylated bisphenol-A diacrylate or dimethacrylate, (3) about 20% to about 60%, based on the total weight of (1) and (2), of ethylene glycol dimethacrylate, and (4) an effective amount of a polymerization catalyst, (c) applying said mixture to said forming surface at ambient temperatures in layers while permitting said layers incrementally to polymerize, thereby building said shaped article, and wherein no more than 20.0 g/m² of volatile emissions as measured by Section 1162 of the Regulations of the South Coast (California) Air Quality District are created, and (d) removing the finished solid formed body from said forming surface.
 2. Method of claim 1 wherein the alkoxylated BPA is a dimethacrylate and has about 2 to about 20 alkoxy groups.
 3. Method of claim 1 wherein said mixture is applied by spraying.
 4. Method of claim 1 wherein said mixture includes glass fibers.
 5. Method of claim 2 wherein said alkoxy groups are ethoxy groups.
 6. Method of making a shaped article comprising (a) repeatedly applying to a form under polymerization conditions, a liquid laminating resin comprising (1) about two parts by weight unsaturated polyester resin, (2) about one to about four parts by weight alkoxylated bisphenol-A diacrylate or dimethacrylate, (3) about 20% to about 60%, based on the total weight of (1) and (2), of ethylene glycol dimethacrylate, and (4) an effective amount of a polymerization catalyst; and (b) permitting said resin to polymerize, wherein a shaped article is manufactured, and wherein no more than 20.0 g/m² as measured by Section 1162 of the Regulations of the South Coast (California) Air Quality District are created. 